The DOI matches its Crossref record; 57 of the 60 references it cites were found in a registry or an index.
Androgen Receptor Gene CAG Repeat Length and Body Mass Index Modulate the Safety of Long-Term Intramuscular Testosterone Undecanoate Therapy in Hypogonadal Men
Abstract
CONTEXT: A reliable form of androgen substitution therapy regarding kinetics, tolerance, and restoration of androgenicity is paramount in hypogonadal men. Intramuscular injection of the long-acting ester testosterone undecanoate (TU) offers a new modality. OBJECTIVE: The objective of the study was to assess the safety of TU regarding metabolic and pharmacogenetic confounders. DESIGN: This was a longitudinal one-arm open observation trial. A minimum of five individual assessments was a prerequisite. Putative modulators of safety parameters entering regression models were nadir and/or delta total testosterone concentrations, body mass index, androgen receptor (AR) gene CAG repeat length, and age. SETTING: The study was conducted at an andrological outpatient clinic. PATIENTS: Patients included 66 hypogonadal men (mean age 38 +/- 9.9 yr). MAIN OUTCOME MEASURES: A total of 515 data time points each related to prostate, erythropoiesis, lipoproteins, and circulation during 118 treatment-years with 1000 mg TU at 10- to 14-wk intervals. RESULTS: Testosterone substitution resulted in significant decrements of serum levels of low-density lipoprotein-cholesterol, resting diastolic and systolic blood pressure, and heart rate. Erythropoiesis was stimulated and concentrations of high-density lipoproteincholesterol increased. Parameters remained stable after four injections. No adverse effects regarding the prostate were observed. Significantly increased hematocrit greater than 50% was predicted by enhanced androgen action (shorter AR CAG repeats per higher testosterone levels). However, insufficient androgen action (longer AR CAG repeats per lower testosterone levels) caused pathological safety parameters (high blood pressure, adverse lipid profiles). In addition, a body mass index 30 kg/m(2) or greater represents a clinically relevant factor for the occurrence of all pathological safety parameters. Risk calculations for obese patients and nonlinear pharmacogenetic models to tailor androgen substitution are presented. CONCLUSIONS: Testosterone substitution with im TU is generally well tolerated. Modifications of androgen action are due to both AR CAG repeats and testosterone levels. Adverse observations are mostly seen in obese patients.
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“Prostate-specific antigen and volume rise, marginally, plateauing at 12 months; further increase should be related to aging rather than therapy.”
From Onset of effects of testosterone treatment and time span until maximum effects are achieved (2011) · cites this paper as [44]
In the citing paper
“The decrease in low-density lipoprotein cholesterol seems somewhat slower: after 3 months (35), after 40–44 weeks, (44) or after 12 months (42) with a maximum observed after 24 months (32).”
From Onset of effects of testosterone treatment and time span until maximum effects are achieved (2011) · cites this paper as [44]
In the citing paper
“An increase was found to occur after 3 months increasing further during 12 months (43), after 6 months, (35) or close to 1 year (44). Continuous increase was observed over 24 months (32).”
From Onset of effects of testosterone treatment and time span until maximum effects are achieved (2011) · cites this paper as [44]
In the citing paper
“A decrease in the resting heart rate occurred after 40–44 weeks (44).”
From Onset of effects of testosterone treatment and time span until maximum effects are achieved (2011) · cites this paper as [44]
In the citing paper
“The effects of testosterone on red blood cell formation (hemoglobin and hematocrit) are dose dependent (14, 82, 83) while higher age is also a factor (44).”
From Onset of effects of testosterone treatment and time span until maximum effects are achieved (2011) · cites this paper as [44]
In the citing paper
“An increase in prostate volume was noted after 3 months (86) and after 12 months (44).”
From Onset of effects of testosterone treatment and time span until maximum effects are achieved (2011) · cites this paper as [44]
Citations
Cites
A Critical Evaluation of Simple Methods for the Estimation of Free Testosterone in Serum
Vermeulen, A., Verdonck, L., & Kaufman, J. M. (1999) · The Journal of Clinical Endocrinology & Metabolism · doi:10.1210/jcem.84.10.6079 · Cited by 3,824
Diabetes and cardiovascular disease during androgen deprivation therapy for prostate cancer
Keating, N. L., O'Malley, A. J., & Smith, M. R. (2006) · Journal of Clinical Oncology · doi:10.1200/jco.2006.06.2497 · Cited by 1,455
Testosterone dose-response relationships in healthy young men
Bhasin, S., Woodhouse, L., Casaburi, R., Singh, A. B., Bhasin, D., Berman, N., Chen, X., Yarasheski, K. E., Magliano, L., Dzekov, C., et al. (2001) · American Journal of Physiology-Endocrinology and Metabolism · doi:10.1152/ajpendo.2001.281.6.e1172 · Cited by 967
Bhasin, S., Cunningham, G. R., Hayes, F. J., Matsumoto, A. M., Snyder, P. J., Swerdloff, R. S., & Montori, V. M. (2006) · The Journal of Clinical Endocrinology & Metabolism · doi:10.1210/jc.2005-2847 · Cited by 965
Calof, O. M., Singh, A. B., Lee, M. L., Kenny, A. M., Urban, R. J., Tenover, J. L., & Bhasin, S. (2005) · The Journals of Gerontology Series A: Biological Sciences and Medical Sciences · doi:10.1093/gerona/60.11.1451 · Cited by 728
Isidori, A. M., Giannetta, E., Greco, E. A., Gianfrilli, D., Bonifacio, V., Isidori, A., Lenzi, A., & Fabbri, A. (2005) · Clinical Endocrinology · doi:10.1111/j.1365-2265.2005.02339.x · Cited by 695
Wang, C., Cunningham, G., Dobs, A., Iranmanesh, A., Matsumoto, A. M., Snyder, P. J., Weber, T., Berman, N., Hull, L., & Swerdloff, R. S. (2004) · The Journal of Clinical Endocrinology & Metabolism · doi:10.1210/jc.2003-032006 · Cited by 656
Association of Specific Symptoms and Metabolic Risks with Serum Testosterone in Older Men
Zitzmann, M., Faber, S., & Nieschlag, E. (2006) · The Journal of Clinical Endocrinology & Metabolism · doi:10.1210/jc.2006-0401 · Cited by 552
Self-citationBhasin, S., Woodhouse, L., Casaburi, R., Singh, A. B., Mac, R. P., Lee, M., Yarasheski, K. E., Sinha-Hikim, I., Dzekov, C., Dzekov, J., et al. (2005) · The Journal of Clinical Endocrinology & Metabolism · doi:10.1210/jc.2004-1184 · Cited by 544
Effect of Testosterone Treatment on Body Composition and Muscle Strength in Men Over 65 Years of Age
Snyder, P. J. (1999) · Journal of Clinical Endocrinology & Metabolism · doi:10.1210/jc.84.8.2647 · Cited by 531
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3 of the 60 references couldn’t be matched to a known paper.
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Items 201–216 of 216
Missbrauch von Anabolen Androgenen Steroiden (AAS)
Vorona, E., & Nieschlag, E. (2021) · Springer Reference Medizin · doi:10.1007/978-3-662-61904-9_37-1
Self-citationNieschlag, E., & Behre, H. M. (2021) · Springer Reference Medizin · doi:10.1007/978-3-662-61904-9_36-1
Self-citationZitzmann, M. (2010) · Elsevier eBooks · doi:10.1016/b978-3-437-24680-7.10044-3
Self-citationSeneszenz und Altershypogonadismus
Rolf, C., Zitzmann, M., & Nieschlag, E. (2023) · Springer Reference Medizin · doi:10.1007/978-3-662-61904-9_25-1
Self-citationSeneszenz und Altershypogonadismus
Rolf, C., Zitzmann, M., & Nieschlag, E. (2023) · Springer Reference Medizin · doi:10.1007/978-3-662-61901-8_25
Self-citationMissbrauch von Anabolen Androgenen Steroiden (AAS)
Vorona, E., & Nieschlag, E. (2023) · Springer Reference Medizin · doi:10.1007/978-3-662-61901-8_37
Self-citationThe Cultural and Medical History of the Testes and Testosterone: From Antiquity to Modern Times
Nieschlag, E., & Nieschlag, S. (2023) · Springer eBooks · doi:10.1007/978-3-031-31501-5_1
Self-citationAbuse of Anabolic Androgenic Steroids (AAS) for Doping
Vorona, E., & Nieschlag, E. (2023) · Springer eBooks · doi:10.1007/978-3-031-31574-9_37 · Cited by 1
Self-citationHoffmann, I., & Behre, H. M. (2024) · Elsevier eBooks · doi:10.1016/b978-0-323-99967-0.00260-x
Die kulturelle und medizinische Geschichte der Hoden und Testosteron: Von der Antike bis zur Moderne
Nieschlag, E., & Nieschlag, S. (2024) · Springer eBooks · doi:10.1007/978-3-031-65245-5_1
Self-citationEscalante, G., Mart, D. S., & Câmara, L. C. (2025) · Strength and conditioning journal · doi:10.1519/ssc.0000000000000931
Erkrankungen der männlichen Gonaden
Hoffmann, I., & Behre, H. M. (2025) · Elsevier eBooks · doi:10.1016/b978-3-437-21184-3.00007-7
The Female-to-Male Medical Treatment
Fabris, B., & Bernardi, S. (2015) · Springer eBooks · doi:10.1007/978-88-470-5696-1_26
Testosterone Deficiency Syndrome
Meryn, S. (2014) · Springer eBooks · doi:10.1007/978-3-662-45018-5_10
Diagnosis and Treatment of Andropause
Özenç, G., & İMAMOĞLU, M. A. (2026) · Springer eBooks · doi:10.1007/978-3-032-28741-0_12
Lewis, D. M. G., Lukaszewski, A. W., Durkee, P. K., Sell, A. N., Sznycer, D., Buss, D. M., Al-Shawaf, L., & Dale, S. P. (2026) · Evolution and Human Behavior · doi:10.1016/j.evolhumbehav.2026.106981
Metadata
- Authors
- Zitzmann, M., & Nieschlag, E.
- Affiliations
- University Hospital Münster (DE)
- Corresponding author
- Nieschlag, Eberhard
- Venue
- The Journal of Clinical Endocrinology & Metabolism
- Publisher
- The Endocrine Society
- Published
- 2007-10-01
- Volume
- 92
- Issue
- 10
- Pages
- 3844-3853
- ISSN
- 0021-972X (ISSN-L)
- 1945-7197
- OpenAlex
- W2127886125
- Cited by
- 216
- References
- 60
- Citations by year
- 2026: 2 · 2025: 3 · 2024: 9 · 2023: 12 · 2022: 2 · 2021: 6 · 2020: 3 · 2019: 8 · 2018: 4 · 2017: 10 · 2016: 9 · 2015: 17 · 2014: 19 · 2013: 15 · 2012: 10
- FWCI
- 16.08
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- The Journal of Clinical Endocrinology & Metabolism (publishedVersion)
- PubMed (publishedVersion)
- Topics
- Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Hormonal and reproductive studies
- Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Adrenal Hormones and Disorders
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Cancer Research › Prostate Cancer Treatment and Research
- Keywords
- testosterone undecanoate, androgen receptor gene, CAG repeat length, hypogonadism, testosterone replacement therapy, body mass index, obesity, pharmacogenetics, lipid profile, blood pressure, erythropoiesis, hematocrit, prostate
- MeSH terms
- Adult, Humans, Hypogonadism, Injections, Intramuscular, Male, Middle Aged, Obesity, Pharmacogenetics, Receptors, Androgen, Regression Analysis, Testosterone, Body Mass Index, Nonlinear Dynamics, Trinucleotide Repeats, Testosterone Congeners
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